Openstack with VMware

We have setup 1 controller node, 1 compute node with KVM, 1 Network node and another compute node for VMWare.
We have .vmdk images into glance and while trying to launch, it goes to KVM. Have few questions
1. Do we need to configure anything in controller node - to say that it has to work with both KVM compute and VMware compute? If yes, what are they?
2. We are seeing availability zones listed in Horizon - under System Info link. How is this created? Do we create it or it comes by default?
3. Also while launching Vm - there is option to select availability zone. For me it lists only one although there are two under 'System Info' menu.

Appreciate your comments/pointers to any document that help understand above concepts.

Comments

Thanks akshik. We tried it the other way - we shutdown the compute host with KVM hypervisor. Now with just the host with nova-compute pointing to VMware, we tried launching instance - sometimes it comes with "No valid host found" error and now with error like "{u'message': u'Network could not be found for bridge br-int', u'code': 404, u'created'".